Search

Radiogenic neutrons emitted by detector materials are one of the most challenging backgrounds for the direct search of dark matter in the form of weakly interacting massive particles (WIMPs). To mitigate this background, the XENONnT experiment is equipped with a novel gadolinium-doped water Cherenkov detector, which encloses the xenon dual-phase time projection chamber (TPC). The neutron veto (NV) tags neutrons via their capture on gadolinium or hydrogen, which release $\gamma$-rays that are subsequently detected as Cherenkov light. In this work, we present the key features and the first results of the XENONnT NV when operated with demineralized water in the initial phase of the experiment. Its efficiency for detecting neutrons is $(82\pm 1)\,\%$, the highest neutron detection efficiency achieved in a water Cherenkov detector. This enables a high efficiency of $(53\pm 3)\,\%$ for the tagging of WIMP-like neutron signals, inside a tagging time window of $250\,\mathrm{\mu s}$ between TPC and NV, leading to a livetime loss of $1.6\,\%$ during the first science run of XENONnT.

The design and performance of wave union TDC implemented in a Lattice CertusPro-NX FPGA is discussed. This FPGA is available for radiation tolerant applications. The TDC is implemented with 16-channels and a 200 MHz reference clock. Each channel is able to record at an event rate of > 1 MHz. The performance of the TDC is assessed over voltage and temperature. Typical TDC performance has a resolution of 10.9 ps. Typical INL is +/-3 LSB peak-to-peak. Typical DNL is (+1.13,-0.77) LSB. Typical differential performance between two channels is 20 ps (1-sigma).

Modeling the motion of ultracold neutrons (UCNs) is crucial for assessing their losses, accurately measuring their lifetime, and describing other experiments. In material traps, it is necessary to account not only for specular but also for diffuse elastic reflection of UCNs from the trap walls. Typically, the Lambert cosine law is used to describe the angular distribution of diffusely scattered neutrons. However, this law lacks a rigorous theoretical derivation and is often violated. In our work, we propose an experiment to measure the deviation of the angular distribution of UCNs during diffuse scattering from the Lambert law. This deviation can be determined by the difference in the number of neutrons exiting through the central and end windows of a long narrow UCN trap. Monte Carlo simulations corresponding to a possible experiment have been performed, demonstrating a significant effect for different trap geometries., Comment: 7 pages, 3 figures, accepted in Pisma v ZhETF vol. 120, issue 12

Since 2022, the LHCb detector has been taking both proton-proton and lead-ion data at the LHC collision rate using a fully software-based trigger. This has been implemented on GPUs at its first stage and CPUs at its second. The setup allows for reconstruction, alignment, calibration and selections to be performed online -- known as the real time analysis paradigm. As well as this, physics analyses are performed using the output of online reconstruction with early results shown using data taken in 2022., Comment: 9 pages, 12 figures, Proceedings from the Connecting the Dots 2023 conference

From 2012 to 2023, the PRISMA-32 array was in operation at the Experimental Complex NEVOD (MEPhI, Moscow). The purpose of the array was to study extensive air showers by detecting the air-shower neutron and electron-photon components using unshielded neutron detectors. To expand the capabilities of this facility, including for the study of cosmic and geophysical phenomena with a neutron flux, its upgrade was carried out. During the upgrade, a dedicated measuring channel for studying variations of the neutron background and the processes affecting these variations was created. To achieve this, the photomultipliers, the integrating amplifiers, the digitalizing electronics and the high-voltage power supply system were replaced. The paper describes the structure of the upgraded array, which was named PRISMA-36, and presents the results of studying the characteristics of the main elements of its "variation" channel. A method for identifying signals caused by neutron capture and the determined criteria for their selection are discussed. An example of a Forbush decrease, caused by a X1.1-class flare and recorded with the variation channel of the PRISMA-36 array, is given., Comment: 19 pages, 21 figures

The ITk is a new silicon tracker for the ATLAS experiment designed to increase detector resolution, readout capacity, and radiation hardness, in preparation for the larger number of simultaneous proton-proton interactions at the High Luminosity LHC. This paper presents the first direct measurement of the material budget of an ATLAS ITk pixel module, performed at a testbeam at the CERN Proton Synchrotron via the multiple scattering of low energy positrons within the module volume. Using a four plane telescope of thin monolithic pixel detectors from the MALTA collaboration, scattering datasets were recorded at a beam energy of $1.2\,\text{GeV}$. Kink angle distributions were extracted from tracks derived with and without information from the ITk pixel module, and were fit to extract the RMS scattering angle, which was converted to a fractional radiation length $x/X_0$. The average $x/X_0$ across the module was measured as $[0.89 \pm 0.01 \text{ (resolution)} \pm 0.01 \text{ (subtraction)} \pm 0.08 \text{ (beam momentum band)}]\%$, which agrees within uncertainties with an estimate of $0.88\%$ derived from material component expectations., Comment: 12 pages, 12 figures

Neutron tagging is a fundamental technique for electron anti-neutrino detection via the inverse beta decay channel. A reported discrepancy in neutron detection efficiency between observational data and simulation predictions prompted an investigation into neutron capture modeling in Geant4. The study revealed that an overestimation of the thermal motion of hydrogen atoms in Geant4 impacts the fraction of captured nuclei. By manually modifying the Geant4 implementation, the simulation results align with calculations based on evaluated nuclear data and show good agreement with observables derived from the SK-Gd data., Comment: 9 pages, 5 figures

Studying the properties of strongly-interacting matter at high relative baryon densities is one of the key scientific goals of the MPD (Multi-Purpose Detector) experiment at the NICA accelerator complex. The performance of measuring the azimuthal collective flow of identified charged hadrons at the MPD facility in fixed-target mode is studied in this work., Comment: 10 pages, in Russian, 8 figures

We present the development of a decay energy spectroscopy (DES) method for the analysis of radioactive impurities using magnetic microcalorimeters (MMCs). The DES system was designed to analyze radionuclides, such as Ra-226, Th-228, and their daughter nuclides, in materials like copper, commonly used in rare-event search experiments. We tested the DES system with a gold foil absorber measuring 20x20x0.05 mm^3, large enough to accommodate a significant drop of source solution. Using this large absorber and an MMC sensor, we conducted a long-term measurement over ten days of live time, requiring 11 ADR cooling cycles. The combined spectrum achieved an energy resolution of 45 keV FWHM, sufficient to identify most alpha and DES peaks of interest. Specific decay events from radionuclide contaminants in the absorber were identified. This experiment confirms the capability of the DES system to measure alpha decay chains of Ra-226 and Th-228, offering a promising method for radio-impurity evaluation in ultra-low background experiments., Comment: 5 pages, 5 figures

A segmented-scintillator-based implantation detector was developed to study the energy distribution of beta-delayed neutrons emitted from exotic isotopes. The detector comprises a 34 $\times$ 34 YSO scintillator coupled to an 8 $\times$ 8 Position-Sensitive Photo-Multiplier Tube (PSPMT) via a tapered light guide. The detector was used at RIBF, RIKEN, for time-of-flight-based neutron spectroscopy measurement in the $^{78}$Ni region. The detector provides the position and timing resolution necessary for ion-beta correlations and ToF measurements. The detector provides a high $\sim$ 80 $\%$ beta-detection efficiency and a sub-nanosecond timing resolution. This contribution discusses the details of the design, operation, implementation, and analysis developed to obtain neutron time-of-flight spectrum and the analysis methods in the context of neutron-rich nuclei in the $^{78}$Ni region.

Modern PET scanners based on scintillating crystals use solid state photo detectors for light readout. The small area of these devices is beneficial for spatial resolution, but also leads to a large number of electronic channels to be read out, mostly by application specific integrated circuits (ASICs) containing amplification, noise reduction, hit finding, time stamping and amplitude measurement. Although each ASIC provides up to $\approx 64$ channels, a large number of chips is required with the need for auxiliary electronic components like voltage regulators or FPGAs for control and data readout. The FPGAs in turn often require multiple supply voltages and configuration infrastructure, so that PCBs get complicated, cumbersome and power-hungry, in addition to the significant power requirement of the front-end ASICs. We address this issue in the latest generation of our PETA readout ASIC for SiPMs by a simplified control scheme and, in particular, by a hierarchical serial data readout which does not require any additional FPGA. In addition, it provides a time-sorted stream of hit data, allowing early on-detector data reduction and hit pre-processing like the removal of hits with no coincident partner. The simplicity of this readout facilitates a supply scheme where power/ground of multiple ASICs are connected in series instead of the standard parallel connection. This 'serial-powering' approach can reduce supply current (while increasing overall supply voltage) so that voltage drop issues in the supply are alleviated., Comment: Contribution to the PETTECH23 Workshop on PET Electronics & Technologies, 12-13.9.2023, Fraunhofer IMS, Duisburg, Germany

Reducing optical losses is crucial for reducing quantum noise in gravitational-wave detectors. Losses are the main source of degradation of the squeezed vacuum. Frequency dependent squeezing obtained via a filter cavity is currently used to reduce quantum noise in the whole detector bandwidth. Such filter cavities are required to have high finesse in order to produce the optimal squeezing angle rotation and the presence of losses is particularly detrimental for the squeezed beam, as it does multiple round trip within the cavity. Characterising such losses is crucial to assess the quantum noise reduction achievable. In this paper we present an in-situ measurement of the optical losses, done for different positions of the beam on the mirrors of the Virgo filter cavity. We implemented an automatic system to map the losses with respect to the beam position on the mirrors finding that optical losses depend clearly on the beam hitting position on input mirror, varying from 42 ppm to 87 ppm, while they are much more uniform when we scan the end mirror (53 ppm to 61 ppm). We repeated the measurements on several days, finding a statistical error smaller than 4 ppm. The lowest measured losses are not much different with respect to those estimated from individual mirror characterisation performed before the installation (30.3 - 39.3 ppm). This means that no major loss mechanism has been neglected in the estimation presented here. The larger discrepancy found for some beam positions is likely to be due to contamination. In addition to a thorough characterisation of the losses, the methodology described in this paper allowed to find an optimal cavity axis position for which the cavity round trip losses are among the lowest ever measured. This work can contribute to achieve the very challenging losses goals for the optical cavities of the future gravitational-wave detectors., Comment: This work has been accepted for publication in Physical Review Applied. The final version is available at https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.22.054040

In this third part of a multi-paper series, we present quantitative image reconstruction results from aerial measurements of eight different surrogate distributed gamma-ray sources on flat terrain. We show that our quantitative imaging methods can accurately reconstruct the expected shapes, and, after appropriate calibration, the absolute activity of the distributed sources. We conduct several studies of imaging performance versus various measurement and reconstruction parameters, including detector altitude and raster pass spacing, data and modeling fidelity, and regularization type and strength. The imaging quality performance is quantified using various quantitative image quality metrics. Our results confirm the utility of point source arrays as surrogates for truly distributed radiological sources, advancing the quantitative capabilities of Scene Data Fusion gamma-ray imaging methods., Comment: 13 pages, 14 figures

In recent decades organic electronics has entered the mainstream of consumer electronics, driven by innovations in scalability and low power applications, and low-cost fabrication methods. The potential for using organic semiconductor electronic devices as radiation detectors, and in particular for neutron detection is reported. We report results of laboratory tests using alpha particles as well as the response to thermal and fast neutrons covering the energy range 0.025 eV to 16.5 MeV. GEANT4 simulations are used to provide a detailed understanding of the performance and potential of this emerging technology for radiation detection., Comment: 2 pages

Sensitive avalanche photodetectors (APDs) that operate within the ultraviolet spectrum are critically required for applications in detecting fire and deep-space exploration. However, the development of such devices faces significant challenges, including high avalanche breakdown voltage, the necessity for complex quenching circuits, and thermal runaway associated with Geiger-mode avalanche operation. To mitigate these issues, we report on a 4H-SiC APD design utilizing micro-holes (MHs) structures and Al nano-triangles (NTs) to enhance surface electric field driven by strong localized surface plasmon excitations and lightning-rod effect. The device demonstrates a record low avalanche breakdown voltage of approximately 14.5 V, a high detectivity of 7E13 Jones, a nanosecond-level response time, and repeated stable detections without the requirement of a quenching circuit. Collectively, when compared with the conventional wide-bandgap-based APDs, this device achieves a reduction in avalanche breakdown voltage by an order of magnitude and exhibits a substantial increase in detectivity. Consequently, the proposed APD configuration presents a promising candidate for ultraviolet detection and integrated optoelectronic circuits.

This paper describes the performance of the LABDOS01, a silicon diode-based spectrometer suitable for dose measurements in mixed radiation fields. The instrument is currently being used in two high-altitude environmental dose monitoring projects: SAMADHA (South Atlantic Magnetic Anomaly Dosimetry at High Altitude) at Chacaltaya (Bolivia, 5240 m a.s.l.) and CORDIAL (COsmic Rays Dosimetry In Antarctic Latitudes) at the Concordia station (Antarctica, 3233 m a.s.l.). Before installing two of these devices at the measurement sites, the detectors were tested on flight routes covering a wide range of geomagnetic latitudes. The collected dosimetric data were compared with the expectations derived by the CARI-7A software, which provides the absorbed dose rate in silicon due to cosmic ray secondaries at a given position on the Earth. The measured dose rates along the flights at variable altitude and rigidity cutoff agree well with the simulated ones. By analyzing the spectrum of the energy deposited in the silicon layer, we derive an empirical method to approximately evaluate the ambient dose equivalent $H^{*}(10)$, a quantity directly related to the biological damage caused by environmental radiation., Comment: Submitted to Radiation Physics and Chemistry

When the variations of surface temperature are measured both spatially and temporally, analytical expressions that correctly account for multi-dimensional transient conduction can be applied. To enhance the accessibility of these accurate multi-dimensional methods, expressions for converting between surface temperature and heat flux are presented as the sum of the one-dimensional component plus the multi-dimensional component. Advantage arises herein because potential numerical challenges are isolated within the one-dimensional component and practitioners are already familiar with well-established one-dimensional methods. The second derivative of the surface heat flux distribution scaled by the thermal diffusivity and the duration of the experiment delivers an approximation of the multi-dimensional conduction term. For the analysis of experiments in which multi-dimensional effects are significant, a simplified numerical approach in which the temperature within each pixel is treated as uniform is demonstrated. The approach involves convolution of temperature differences and pixel-based impulse response functions, followed by a summation of results across the region of interest, but there are no singularities that require special treatment in the multi-dimensional component. Recovery of heat flux distributions to within 1% is demonstrated for two-dimensional heat flux distributions discretized using several tens of elements, and for a three-dimensional distribution discretized using several hundred pixels. Higher accuracy can be achieved by using finer spatial resolution, but the level of discretization used herein is likely sufficient for practical applications since typical experimental uncertainties are much larger than 1%.

The Torsion-Bar Antenna (TOBA) is a torsion pendulum-based gravitational detector developed to observe gravitational waves in frequencies between 1 mHz and 10 Hz. The low resonant frequency of the torsion pendulum enables observation in this frequency band on the ground. The final target of TOBA is to observe gravitational waves with a 10 m detector and expand the observation band of gravitational waves. In this paper, an overview of TOBA, including the previous prototype experiments and the current ongoing development, is presented.

We demonstrate the advantages of THz frequency combs for high-resolution spectroscopy. This benefits from wide spectral coverage and the exact knowledge of the frequency position of each comb component. Heterodyne detection combined with a fast Fourier spectrometer enables rapid and simultaneous measurement of more than 80 frequency comb modes covering a 7.5 GHz bandwidth. A spectrum is obtained in under 20 minutes yielding a uniform resolution of 70 kHz. This new setup has been validated by recording more than 150 lines of methanol around 723 GHz, and represents a new solution to exploit THz frequency combs for high-resolution spectroscopy.

High resolution rotational Terahertz (THz) spectroscopy has been widely applied to the studies of numerous polar gas phase molecules, in particular volatile organic compounds (VOCs). During the storage of foodstuffs packed under a protective atmosphere, microbial activity will lead to the generation of a complex mixture of trace gases that could be used as food spoilage indicators. Here we have demonstrated that the THz instrumentation presently available provides sufficient sensitivity and selectivity to monitor the generation of hydrogen sulfide (H2S) in the headspace of packed Atlantic salmon (Salmo salar) fillet portions. A comprehensive comparison was made by selective-ion flow-tube mass spectrometry (SIFT-MS) in order to validate the THz measurements and protocol. The detectivity of a range of alternative compounds for this application is also provided, based on the experimental detection limit observed and molecular spectroscopic properties. Molecules like ethanol, methyl mercaptan and ammonia are suitable indicators with the presently available sensitivity levels, while dimethyl sulfide, acetone and butanone may be considered with a sensitivity improvement of 2 orders of magnitude.

We report on experimental investigation of potential high-performance cavity length stabilization using odd-indexed higher-order spatial modes. Schemes based on higher-order modes are particularly useful for micro-cavities that are used for enhanced fluorescence detection of a few emitters, which need to minimize photons leaking from a stabilization beam. We describe the design and construction of an assembly for a microcavity setup with tunable high passive stability. In addition, different types of active stabilization techniques based on higher-order modes, are then implemented and characterized based on their performance. We achieved a stability of about 0.5 pm RMS, while the error photons leaking from the continuous locking beam to a fluorescence detector are suppressed by more than 100-fold. We expect these results to be important for quantum technology implementations of various emitter-cavity setups, where these techniques provide a useful tool to meet the highly challenging demands.

The prospects of using last version of a compact supermirror transmission polarizer TRUNPOSS on silicon in modern neutron research facilities of the instrumental base being created for the PIK reactor (PNPI, Gatchina, Russia) will discuss in the paper. The results of calculations of the parameters and main characteristics of this polarizer for using it in IN2, IN3, SEM, DEDM, TENZOR facilities are discussed in detail., Comment: 21 pages, 22 figures

The TOTEM Roman pot detectors are used to reconstruct the transverse momentum of scattered protons and to estimate the transverse location of the primary interaction. This paper presents new methods of track reconstruction, measurements of strip-level detection efficiencies, cross-checks of the LHC beam optics, and detector alignment techniques, along with their application in the selection of signal collision events. The track reconstruction is performed by exploiting hit cluster information through a novel method using a common polygonal area in the intercept-slope plane. The technique is applied in the relative alignment of detector layers with $\mu$m precision. A tag-and-probe method is used to extract strip-level detection efficiencies. The alignment of the Roman pot system is performed through time-dependent adjustments, resulting in a position accuracy of 3 $\mu$m in the horizontal and 60 $\mu$m in the vertical directions. The goal is to provide an optimal reconstruction tool for central exclusive physics analyses based on the high-$\beta^*$ data-taking period at $\sqrt{s}$ = 13 TeV in 2018., Comment: Submitted to the Journal of Instrumentation. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/SMP-23-006 (CMS Public Pages)

Laser triangulation sensors are widely used in industry for surface inspection due to simple setup, micron precision and low cost. Conventional laser triangulation methods only enable axial distance measurement limiting further applications, and their lateral resolution is limited by surface microstructure. For overcoming these issues, based on the geometric optics we propose novel theoretical models and methods to achieve lateral velocity measurement. Moreover, a novel axial distance measurement method using edge detection is presented, which can increase the lateral resolution by the order of one magnitude. The performance of the proposed methods are validated through simultaneous orthogonal velocity and distance measurements on a moving established metal specimen, showing the relative error and relative uncertainty can reach 10^{-4}. The versatility of this multi degree of freedom measurement method paves the way for its broad application across all laser triangulation systems. Therefore, this simultaneous two-dimensional velocity and distance sensing approach can propel advancements in dynamic behavior discipline, including but not limited to motion mechanology and fluid mechanics.

We calculate the effects of carrier-density structuration and patterning on thin films of the cuprate superconductor La$_{2-x}$Sr$_{x}$CuO$_{4}$, in order to optimize its functional characteristics as sensing material for resistive transition-edge bolometers at liquid-He temperature. We perform finite-element computations considering two major contributions to structuration: The intrinsic random nanoscale disorder associated to carrier density nonstoichiometry, plus the imposition of regular arrangements of zones with different nominal carrier densities. Using ad-hoc seek algorithms, we obtain various structuration designs that markedly improve the bolometric performance, mainly the saturation power and dynamic range. Bolometric operation becomes favorable even in the easier-to-implement constant current mode of measurement., Comment: 28 pages, 3 figures plus a graphical abstract, 1 table

A film of liquid helium on the surface of material traps for ultracold neutrons protects the neutrons from being absorbed by the trap walls. By using surface roughness and an electrostatic field, it is possible to maintain a helium film of sufficient thickness throughout the height of the trap. The field distribution near the tip of such wall roughness of the trap was calculated, and the effect of this field on holding the helium film was estimated., Comment: 6 pages, 3 figures

The results of the analysis of solid-state track detectors CR39 and nuclear photoemulsion plates irradiated in beams of accelerated xenon ions with energies of 3.2 MeV/n and 3.8 GeV/n at the NICA accelerator complex are presented., Comment: The article to be published in PEPAN journal as proceedings of Scientific session of the nuclear physics section of the Physical Sciences Department of the Russian Academy of Sciences (https://indico.jinr.ru/event/4174/)

We report on measurements of 1 and 1.5 MeV monoenergetic electrons with a Timepix3-based detector using a 0.5 mm thick silicon sensor. A $^{90}$Sr $\beta$-emitting radioisotope was used as the source of electrons, and a monochromator equipped with an adjustable magnetic field was employed to only pass electrons of desired energy into the detector. We provide experimental results of deposited-energy spectrum in the sensor and linearity of detected tracks. Alongside with the experiment, the whole system has been modelled in software and a Monte Carlo Geant4 / Allpix$^2$ simulation of the experiment has been carried out. Generally, we find a good agreement between the two., Comment: 9 pages, 5 figures

The Gamma-Ray Transient Monitor (GTM) is an all-sky monitor onboard the Distant Retrograde Orbit-A (DRO-A) satellite, with the scientific objective of detecting gamma-ray bursts in the energy range of 20 keV to 1 MeV. The GTM is equipped with five Gamma-Ray Transient Probes (GTPs), utilizing silicon photomultiplier (SiPM) arrays coupled with NaI(Tl) scintillators for signal readout. To test the performance of the GTP in detecting electrons, we independently developed a continuous-energy-tunable, low-current, quasi-single-electron accelerator, and used this facility for ground-based electron calibration of the GTP. This paper provides a detailed description of the operational principles of the unique electron accelerator and comprehensively presents the process and results of electron calibration for the GTP. The calibration results indicate that the dead time for normal signals is less than 4 $\mu$s, while for overflow signals, it is approximately 70 $\mu$s, consistent with the design specifications. The GTP's time-recording capability is working correctly, accurately recording overflow events. The GTP responds normally to electrons in the 0.4-1.4 MeV energy range. The ground-based electron calibration validates the design of the GTP and enhances the probe's mass model, laying the foundation for payload development, in-orbit observation strategies, and scientific data analysis., Comment: 14 pages, 16 figures

Challenging neutron-capture cross-section measurements of small cross sections and samples with a very limited number of atoms require high-flux time-of-flight facilities. In turn, such facilities need innovative detection setups that are fast, have low sensitivity to neutrons, can quickly recover from the so-called $\gamma$-flash, and offer the highest possible detection sensitivity. In this paper, we present several steps toward such advanced systems. Specifically, we describe the performance of a high-sensitivity experimental setup at CERN n\_TOF EAR2. It consists of nine sTED detector modules in a compact cylindrical configuration, two conventional used large-volume C$_{6}$D$_{6}$ detectors, and one LaCl$_{3}$(Ce) detector. The performance of these detection systems is compared using $^{93}$Nb($n$,$\gamma$) data. We also developed a detailed \textsc{Geant4} Monte Carlo model of the experimental EAR2 setup, which allows for a better understanding of the detector features, including their efficiency determination. This Monte Carlo model has been used for further optimization, thus leading to a new conceptual design of a $\gamma$ detector array, STAR, based on a deuterated-stilbene crystal array. Finally, the suitability of deuterated-stilbene crystals for the future STAR array is investigaged experimentally utilizing a small stilbene-d12 prototype. The results suggest a similar or superior performance of STAR with respect to other setups based on liquid-scintillators, and allow for additional features such as neutron-gamma discrimination and a higher level of customization capability.

A front-end readout system with a large dynamic range is required for the high-granularity crystal ECAL at future Higgs factories. A new commercially available ASIC, MPT2321-B, which offers a significantly large dynamic range for the readout of the SiPM, has undergone initial tests both in the laboratory and at a beamtest facility. The fundamental performance metrics, including response linearity and single photon sensitivity, have been characterised. To quantitatively assess the dynamic range of the chip and evaluate its feasibility for SiPM readout in high-granularity crystal ECAL, a beamtest was conducted using scintillating crystals exposed to electron beams. Observations confirmed that the chip exhibits a signal-to-noise ratio sufficient for the operation of the detector and a satisfactory dynamic range, indicating significant potential for future applications.

The resolution of low-frequency resistance noise measurements is increased by amplitude modulation, shifting the spectrum of the resistance fluctuations away from the 1/f noise contributed by measurement instruments. However, commercial lock-in amplifiers used for de-modulating the fluctuations exhibit a problematic 1/f noise contribution, which imposes a hard lower limit on the relative resistance noise that can be detected. We replace the lock-in amplifier hardware by equivalent digital signal processing performed using open-source software and inexpensive data acquisition systems. Our solution offers superior low-frequency noise performance with a reduction of the voltage power spectral density by about two orders of magnitude compared to high-end commercial instruments.

The p-type point-contact germanium (pPCGe) detectors have been widely adopted in searches for low energy physics events such as neutrinos and dark matter. This is due to their enhanced capabilities of background rejection, sensitivity at energies as low as the sub-keV range and particularly fine energy resolution. Nonetheless, the pPCGe is subject to irregular behaviour caused by surface effects for events near the passivated surface. These surface events can, in general, be distinguished from events that occur in the germanium crystal bulk by its slower pulse rise time. Unfortunately, the rise-time spectra of bulk and surface events starts to convolve with each other at sub-keV energies. In this work, we propose a novel method based on cross-correlation shape-matching combined with a low-pass filter to constrain the initial parameter estimates of the signal pulse. This improvement at the lowest level leads to a 50% reduction in computation time and refinements in the rise-time resolution, which will, in the end, enhance the overall analysis. To evaluate the performance of the method, we simulate artificial pulses that resembles bulk and surface pulses by using a programmable pulse generator module (pulser). The pulser-generated pulses are then used to examine the pulse behaviours at near-threshold energies, suggesting a roughly 70% background-leakage reduction in the bulk spectrum. Finally, the method is tested on data collected from the TEXONO experiment, where the results are consistent with our observations in pulser and demonstrated the possibility of lowering the analysis threshold by at least 10eV.

OASIS-UROS continues the previously published Open Acquisition System for IEPE Sensors (OASIS). While still building on the ESP32 microcontroller, this version improves the overall performance by switching to an SD card caching system and upgrading the analog-digital converter to an AD7606C-18, which has a higher resolution, provides eight channels, oversampling, and software-adjustable voltage ranges. Also improved is the IEPE front-end and power supply, as well as the firmware of the acquisition system, which can now achieve a sample rate of up to 36 kHz while sampling all eight channels. This paper documents the hardware and software of OASIS-UROS and provides all materials required to reproduce the open acquisition system. Lastly, the system was validated against commercial hardware and software in an experimental modal analysis context. This showed that the system performs close to the commercial one in some aspects with respect to the utilized test case. While OASIS-UROS cannot match the full performance of the commercial system, the developed system can be a viable alternative for students, people in academia, or smaller companies that have a constrained budget or require complete insight as well as adaptability of the hardware and software.

Wire media (WM) resonators have emerged as promising realization for plasma haloscopes -- devices designed to detect axions, a potential component of dark matter. Key factors influencing the detection probability include cavity volume, resonance quality factor, and form factor. While the form factor has been explored for resonant frequency tuning, its optimization for axion detection remains unexplored. In this work, we present a novel approach to significantly enhance the form factor of WM plasma haloscopes. By shifting the metal walls of the resonator by a quarter wavelength, we effectively convert an electric wall boundary condition into a magnetic wall one, allowing for an almost uniform mode. Theoretical analysis and numerical simulations confirm that this modification improves the electric field profile and boosts the form factor. We validate these findings through experimental results from two prototype resonators: one with a standard geometry and another with a quarter-wave air gap between the WM and the walls. Additionally, our method provides a simple way to control the field profile within WM cavities, which can be explored for further applications.

Bubbles are ubiquitous in many research applications ranging from ultrasound imaging and drug delivery to the understanding of volcanic eruptions and water circulation in vascular plants. From an acoustic perspective, bubbles are resonant scatterers with remarkable properties, including a large scattering cross-section and strongly sub-wavelength dimensions. While it is known that the resonance properties of bubbles depend on their local environment, it remains challenging to probe this interaction at the single-bubble level due to the difficulty of manipulating a single resonating bubble in a liquid. Here, we confine a cubic bubble inside a cage using 3D printing technology, and we use this bubble as a local probe to perform scanning near-field acoustic microscopy -- an acoustic analogue of scanning near-field optical microscopy. By probing the acoustic interaction between a single resonating bubble and its local environment, we demonstrate near-field imaging of complex structures with a resolution that is two orders of magnitudes smaller than the wavelength of the acoustic field. As a potential application, our approach paves the way for the development of low-cost acoustic microscopes based on caged bubbles.

Heterodyne detection using microwave cavities is a promising method for detecting high-frequency gravitational waves or ultralight axion dark matter. In this work, we report on studies conducted on a spherical 2-cell cavity developed by the MAGO collaboration for high-frequency gravitational waves detection. Although fabricated around 20 years ago, the cavity had not been used since. Due to deviations from the nominal geometry, we conducted a mechanical survey and performed room-temperature plastic tuning. Measurements and simulations of the mechanical resonances and electromagnetic properties were carried out, as these are critical for estimating the cavity's gravitational wave coupling potential. Based on these results, we plan further studies in a cryogenic environment. The cavity characterisation does not only provide valuable experience for a planned physics run but also informs the future development of improved cavity designs., Comment: 23 pages, 17 figures

Objective: Proton therapy is a precision-focused cancer treatment where accurate proton beam range monitoring is critical to ensure effective dose delivery. This can be achieved by prompt gamma detection with a Compton camera like the SiFi-CC. This study aims to show the feasibility of optimising the geometry of SiFi-CC Compton camera for verification of dose distribution via prompt gamma detection using a genetic algorithm (GA). Approach: The SiFi-CC key geometric parameters for optimisation with the GA are the source-to-scatterer and scatterer-to-absorber distances, and the module thicknesses. The optimisation process was conducted with a software framework based on the Geant4 toolkit, which included detailed and realistic modelling of gamma interactions, detector response, and further steps such as event selection and image reconstruction. The performance of each individual configuration was evaluated using a fitness function incorporating factors related to gamma detection efficiency and image resolution. Results: The GA-optimised SiFi-CC configuration demonstrated the capability to detect a 5 mm proton beam range shift with a 2 mm resolution using 5e8 protons. The best-performing geometry, with 16 fibre layers in the scatterer, 36 layers in the absorber, source-to-scatterer distance 150 mm and scatterer-to-absorber distance 120 mm, has an imaging sensitivity of 5.58(1)e-5. Significance: This study demonstrates that the SiFi-CC setup, optimised through a GA, can reliably detect clinically relevant proton beam range shifts, improving real-time range verification accuracy in proton therapy. The presented implementation of a GA is a systematic and feasible way of searching for a SiFi-CC geometry that shows the best performance., Comment: 10 figures, 3 tables

The aim of the presented work is the development of single-stage amplification resistive Micro Pattern Gas Detectors (MPGD) based on Micromegas technology with the following characteristics: ability to efficiently operate up to 10 MHz/cm$^2$ counting rate; scalability to large areas; fine granularity readout with small pads of the order of mm$^2$; good spatial and time resolutions (below 100 $\mu$m and 10 ns, respectively). The miniaturization of the readout elements and the optimization of the spark protection system, as well as the stability and robustness under operation, are the primary challenges of the project. Two families of resistive patterns were realized using different techniques: pad-patterned embedded resistors and double-layer of Diamond Like Carbon (DLC) structures foils. Their main difference is that for the embedded resistors the charge is evacuated through independent pads, for double-layer DLC the resistive layers are continuous and uniform and the charge is evacuated through a network of dot-connections, several millimetres apart. Using the DLC technique, a medium-size detector with an active area of 400 cm$^2$ was recently built and tested, with the main results reported in this paper. Additionally, a large module (50x40 cm$^2$ active area), suitable for tiling large systems in future experiments, has been successfully realised and is currently undergoing testing and performance studies. The characterization and performance studies of the detectors were conducted using radioactive sources and an X-rays generator, with the detectors operated with various gas mixtures. A comparison of the results obtained with different resistive layouts and configurations is provided, with a particular focus on the response under high-rate exposure. Key results on tracking and timing performance from test-beam data for the latest constructed medium-size detector are also presented., Comment: submitted to JINST

We present experimental results of the cross-section related to cosmic-ray irradiation at ground level for minimum-sized six-transistors (6T) and eight-transistors (8T) bit-cells SRAM memories implemented on a 65 nm CMOS standard technology. Results were obtained from accelerated irradiation tests performed in the mixed-field irradiation facility of the CERN High-energy Accelerator test facility (CHARM) at the European Organization for Nuclear Research in Geneva, Switzerland. A 1.45x higher SEU cross-section was observed for 6T-cell designs despite the larger area occupied by the 8T cells (1.5x for MCU). Moreover, the trend for events affecting multiple bits was higher in 6T-cells. The cross-section obtained values show that the memories have enough sensitivity to be used as a radiation monitors in high energy physics experiments., Comment: 18 pages, 8 figures

In some types of mass spectrometers, such as Time of Flight mass spectrometers (TOF-MSs), it is necessary to control pulsed beams of ions. This can be easily accomplished by applying a pulsed voltage to the pusher electrode while the ionizer is continuously flowing ions. This method is preferred for its simplicity, although the ion utilization efficiency is not optimized. Here we employed another pulse-control method with a higher ion utilization rate, which is to bunch ions and kick them out instead of letting them stream. The benefit of this method is that higher sensitivity can be achieved; since the start of new ions cannot be allowed during TOF separation, it is highly advantageous to bunch ions that would otherwise be unusable. In this study, we used analytical and numerical methods to design a new bunching ionizer with reduced resources, adopting the principle of electrostatic ion beam trap. The test model experimentally demonstrated the bunching performance with respect to sample gas density and ion bunching time using gas samples and electron impact ionization. We also conducted an experiment in connection with a miniature TOF-MS, and showed that the sensitivity was improved by more than one order of magnitude using the newly developed ionizer. Since the device is capable of bunching ions with lower voltage and lower power consumption (~100 V, ~0.8 W) compared with conventional RF ion trap bunchers (several kilovolts, ~10 W), it will be possible to find applications in portable mass spectrometer with reduced resources.

Liquid argon detectors rely on wavelength shifters for efficient detection of scintillation light. The current standard is tetraphenyl butadiene (TPB), but it is challenging to instrument on a large scale. Poly(ethylene 2,6-naphthalate) (PEN), a polyester easily manufactured as thin sheets, could simplify the coverage of large surfaces with wavelength shifters. Previous measurements have shown that commercial grades of PEN have approximately 50% light conversion efficiency relative to TPB. Encouraged by these results, we conducted a large-scale measurement using $4~m^2$ combined PEN and specular reflector foils in a two-tonne liquid argon dewar to assess its stability over approximately two weeks. This test is crucial for validating PEN as a viable substitute for TPB. The setup used for the measurement of the stability of PEN as a wavelength shifter is described, together with the first results, showing no evidence of performance deterioration over a period of 12 days., Comment: 10 pages, 13 figures

Accurate characterization of radiation pulse profiles is crucial for optimizing beam quality and enhancing experimental outcomes in Free Electron Laser (FEL) research. In this paper, we present a novel approach that employs machine learning techniques for real-time virtual diagnostics of FEL radiation pulses. Our advanced artificial intelligence (AI)-based diagnostic tool utilizes longitudinal phase space data obtained from the X-band transverse deflecting structure to reconstruct the temporal profile of FEL pulses in real time. Unlike traditional single-shot methods, this AI-driven solution provides a non-invasive, highly efficient alternative for pulse characterization. By leveraging state-of-the-art machine learning models, our method facilitates precise single-shot measurements of FEL pulse power, offering significant advantages for FEL science research. This work outlines the conceptual framework, methodology, and validation results of our virtual diagnostic tool, demonstrating its potential to significantly impact FEL research., Comment: 9 pages , 5 figures